ted blocks.  Indented
    blocks trigger a new state machine to be created by `indent()` and run.
    The class of the state machine to be created is in `indent_sm`, and the
    constructor keyword arguments are in the dictionary `indent_sm_kwargs`.

    The methods `known_indent()` and `firstknown_indent()` are provided for
    indented blocks where the indent (all lines' and first line's only,
    respectively) is known to the transition method, along with the attributes
    `known_indent_sm` and `known_indent_sm_kwargs`.  Neither transition method
    is triggered automatically.
    Nz